Method for separating starch and gluten



June 12, 1951 K|| ANDER 2,557,032

METHOD FOR SEPARATING STARCH AND GLUTEN Filed March 5, 1946 2 Shasta-Sheet l INVENTOR Ha o/1 170% iii/and km zb m ATTORNEY June 12, 1951 Filed March 5, 1946 A. K. KILANDER METHOD FOR SEPARATING STARCH AND GLUTEN 2 Sheets-Sheet 2 ATTORNEY Patented June 12, 1951 UNITED STATES PATENT OFFICE METHOD FOR SEPARATI'NG STARCH AND GLUTEN Acton Keith Kilander, Gibraltar, Mich, assignor, by mesne assignments, to Trenton Chemical Company, Trenton, Mich., a corporation of Michigan Application March 5, 1946, Serial No. 652,140

Claims.

the separation of starch and gluten from ordi-- nary wheat flour. The present invention is herein illustrated in part as an improvement on that prior patent application and in part as a process in which new temperature control initiates conversion of the starch to sugar, if desired, thus providing a considerably converted starch for the process of preparing the material for the production of alcohol; it is also illustrated in part as an apparatus and process especially adapted for the separation and recovery of the gluten content of durum wheat flour.

- Ithas long been known that durum wheats contain a larger proportion of gluten than do ordinary wheat flours and also are lower in price than many other wheat flours, but attempts to separate gluten from the flour of durum wheat proved failures commercially. Durum wheat flour, if agitated with water, made a paste instead of a dough when used in the same proportions that made a dough with ordinary wheat flour. Addition of further water to the durum wheat paste and then agitating failed to properly agglomerate the gluten in particles that could be satisfactorily screened out or satisfactorily separated from the starch water. Durum wheat flour is said to have inferior wettability compared with other wheat flour.

According to one form of the present invention these difliculties and objections encountered in recovering gluten from durum wheat flour are overcome and a larger yield of gluten is obtained at a lower cost; at the same time a highly useful starch water is separated suitable for fermenta tion or for the production of dry wheat starch, Moreover, the process may be so operated in using any wheat flour as to partially convert the contained starch to sugar ready for fermentation, and thus substantially reduce the time and ma; terials needed for complete conversion to fermentable sugars.

In the form shown the durum wheat flour is admixed with ordinary wheat flour of the type hitherto used for the production of gluten, and

2 the flour is then mixed with about an equal weight of water to form a dough and later agitated with added water to form gluten agglomerates which are screened out and then further agitated with added water and again screened.

The water from this second screening preferably provides the added water for the first agitation.

The gluten from the second screen is then shown as delivered to hot devitalizing tanks and then dried.

In the form described in some detail, the durum wheat flour is mixed with about an equal weight of ordinary flour, since proportions of durum up to that amount or thereabouts give increasing yields of gluten and usually operate smoothly and efiicientlyin the process. If much larger proportions of the durum flour are added the yields of gluten are usually reduced, the dough becomes pasty and the mixture turns out to be diflicult to put through the process shown.

It is found that the method of mixing the first dough exercises a considerable effect on thesubsequent separation Apparently the gluten is caused to agglutinate better if the screw-conveying mixer is interrupted so as to provide a pool where the mixture comes to rest and then is carried on by a second screw-conveyor. As many as three such pools prove useful in conveying the dough from the mixing sieve, where it is formed, to the agitator where it is agitated with added water and then the gluten screened out.

In order to operate the process with maximum efficiency the relative proportions of flour and water must be accurately controlled at various points, especially in the mixing to make the dough at the first step of the process, although the exact proportion of water to produce the best results may vary with the type of flour and with the temperature of working.

Also where the diverse types of flours are mixed as an incident to operating the process, varying the exact proportions of each used mayseriously alter the eificiency of the process.

Thus it becomes important to assure an even feeding of the flour or flours used and to minimize or forestall any tendency of the flours to block by bridging within the feed bins or silos.

It has been found possible to minimize or eliminate the tendency to bridge by providing within thebins freely swinging baflle plates which extend from near the bottoms of the conical bottoms of the bins to a point above the conical wall. Such baflle plates are highly effective when set in several rows of separately swinging plates,

3 and require no attention, and do not deteriorate or wear out.

It has been found possible to effectively dr the gluten by a process which includes delivering the oncoming wet gluten to a stream of previously dried gluten, sending part, perhaps half, of the mixed stream to a recirculating drier, and delivering the remainder of the mixed stream to a finishing drier.

Thus a continuously circulating stream of gluten is continually receiving wet gluten and is continually delivering part of the stream to be finally dried and shipped out as a finished product.

One of the objects of the present invention is to assure the even downward flow of flour in the feed bins by a simple device requiring no attention.

Another object of the invention is to increase the yield of gluten from wheat flour.

Another object of the invention is to provide" a more economical and smoothly operating process for the production of gluten.

Another object of the invention is to produce an equally good gluten from lower priced flours.

Another object of the invention is to improve the agglomeration of the gluten to facilitate its separation.

Another object of the invention is to utilize simple steps to improve the agglomeration of the gluten.

Another object of the invention is to provide an improved drying procedure and apparatus for drying gluten.

Another object of the invention is to provide a process for recovering gluten from durum wheat flour.

Another object of the invention is to utilize natural enzymes of the wheat to initiate conversion of starch into sugars preparatory to fermen tation.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings, forming a part of the specification, wherein:

Fig. 1 is a flow sheet showing diagrammatically one form of apparatus suitable for carrying out the process, with some alternatives indicated;

Fig. 2 shows diagrammatically an alternative drying arrangement;

Fig. 3 is a sectional view looking down into one form of flow bin showing one form of antibridging baffle plates;

Fig. 4 is 'a sectional view along the line fi-4 of Fig. 3 showing a side view of the baiile plate structure; and Fig. 5 is a diagrammatic plan View of the second gluten screens showing them located over the devitalizing tank.

In the form shown an ordinary type of wheat flour is stored in a bin l0 so that its flow may be controlled by bafii'es ll (Fig. 3) as it flows into the bin through the usual steel grating l2 which has meshes about 1 inch by 2 inches to takeout large waste elements.

In the form shown durum what flour is stored in a bin l4 located beside the bin m and which may be identical, having a grating and bafiies ll.

Each of the bins [El and I4 is preferably provided with a constant weight feeder IT and a separate control valve i8 to enable independently measured quantities of each flour to be de livered to a sifter is where the two flours are carefully and thoroughly mixed before wetting and are sifted to take out lumps.

Imperfect mixing may cause difficulties. Usually the most eflicient results are obtained when about equal parts of the durum and the ordinary wheat flour are mixed, but the quality of the flours used may alter proportions either way for best results.

A smaller proportion of the durum flour demands a larger proportion of the more expensive flour. A larger proportion of the durum flour usually yields an unsatisfactory dough and raises other problems in operating the process.

In the form shown the mixed flour drops into the small end of a tapered conveyor 26 having a pair of screw conveyors 2 i, one of which is shown in Fig. 1, adapted to be driven at a variable speed by a motor 22 connected by a suitable gearing 23.

The tapering oi the conveyor 26 and the presence of the bailles H prevent or minimize bridging of the flour.

The tapered conveyor 2i] delivers flour to a second screw conveyor 28 having flights 25 in the form shown, and preferably of eight inches diameter which is double the four inches of the conveyor iii.

The second conveyor is, like the first conveyor 26, is shown as feeding the flour upwardly at an angle of about 30 degrees for a considerable distance to a point 27 where the turns or flights 25 of its screw terminate.

Water is added from a constant head tank 25a at about the end 26 of the tapered conveyor 20. usually hot water, hot enough to bring the resulting dough to a temperature of about 40 F. to F. in instances where starch is desired as an end product, or to about F. in instances where alcohol is to be made.

The amount of water fed is rather critical in its eifect, depending a little on the flour used. Usually about a pound of Water per pound of flour T is most satisfactory, and the quantity of water added is easily automatically regulated at 24a within a half-gallon a minute which in the device shown was about 2% plus or minus. A variation of 10% in the proportions afiects the final yield.

For about two feet beginning at the end 21 of the screw 25 the screw is shown broken away so that a sizable pool 3| of dough forms there and seems to let the gluten begin to agglutinate. At 28 about two feet from the point 21, new flights 30 of the screw 25 again feed the dough onwardly, preferably about half the distance it was fed by the flights 25, and then end to form a second pool 32 which may be somewhat shorter than the pool 3 I The screw includes further flights 33' which terminate short of the end 34 of the conveyor thus forminga third pool 35 where the dough pauses before its drops into a retention chamber 36. Here the dough is slowly, very slowly, agitated for a number of minutes by incoming and outgoing dough. Ten or fifteen minutes has been found useful. The chamber 36 also serves to provide storage for dough in case of interruption of opera tion of a conveyor 25 or of the washer 40, described below.

From the conical bottom 31 of the chamber 36. the dough is fed diagonally upward by a con veyor 38 which may be a screw or ribbon conveyor,

and is dumped into a primary agitation tank or tall round washer where water, preferably recovered water, is addedfrom a hot water line 4| to make altogether about four pounds of water to one pound of flour.

The washer 40 is found most satisfactory if round and vertical, being shown half as high again as across. This shape facilitates circulation and breaking up of lumps, but not so violently as to break up the gluten agglomerates.

Agitation is satisfactory when a centrifugal pump 42 draws off the liquid through a bottom outlet 43 at the end of the conical bottom 44 and recirculates a large part of the pump feed through a Hills-McCanna valve 45 and return pipe 46 into the washer 40 somewhat below its middle, while the remainder of the pump feed is diverted by the valve 45 to a screen feed pipe 41 which delivers that part of the pump eflluent to primary inclined vibrating screens 43, by distributing pipes 50.

In the form shown there are three screens 48 about three feet by four feet, each of two sections, preferably made of ISO-mesh stainless steel wire cloth of diameter of 0.0135.

To avoid clogging, the distributing pipes 50 may be provided with plug cocks 5|. Each screen receives the liquid by a spreader 52, and the distributed sheet of liquid is preferably received by a canvas bafile to keep the liquid mixture from impinging on the screen with sufiicient violence to force gluten particles through the screen.

The gluten retained by the screens 48 rolls down them into a hopper 54 and chute 55 which delivers the separated-out gluten to a second agitation tank or washer 56.

Meanwhile the starch water passing through the screens 48 is gathered by a funnel 51 and pumped oif as finished starch water by a pump 58 and delivered to a storage tank 59.

A return connection pipe may return starch water to the washer 56 if need be to control the specific gravity of the starch water which is preferably about 1.073 to 1.084. The main current of the starch water may be carried by the line 6| from the pump 58 under the control of a liquid level control 62 and fed to the outside storage tank diagrammatically shown at 59, or it may go to a starch making plant at 63. The control 62 may return starch water to the circuit, shown as going through a valved pipe 62a which is shownas delivering to the washer 55, with the result that it eventually returns to the washer 40.

In the form disclosed in some detail the starch is eventually used for fermenting for the production of alcohol to be recovered by rectification.

To produce alcohol most efiiciently the starch water in the tank 59 is preferably held at a temperature of 135 F. to 145 F., facilitating the action of natural enzymes of the wheat'in changing starch to sugar, thus reducing the amount of malt required for subsequent fermentation.

When this result is sought, the temperature of the entire process, including the first and second washings, is preferably maintained at about 120 F. so that during all operations some of the starch is being changed into sugar. It is found that proper maintenance of such temperatures results in thechanging of 15% to 25% of the starch into sugar. This enables the fermentation process to be economically operated by adjusting down to the lesser amount of starch to be treated by fermentation.

If the starch water is tobe treated to yield 5 pure dry starch, temperatures in the neighborhood of 90 F. to 105 F. are usually more satisfactory in the dough mixer and temperatures of 40 F. to F. in the washers.

The second agitation tank or washer 56 may be.

identical with, the washer 40 including a conical bottom 66 and a centrifugal pump 6'! circulating the contents drawn through a pipe 68 at the bottom of the conical bottomand delivering the pumped and agitated contents to the side 69 of the washer 56, below its middle through a pipe 15 provided with a Hills-McCanna valve 'H..

The valve 1 l separates out part of the material in the pipe 10 diverting it to a pipe 12 which conveys the contents to secondary screens 14 which may be identical with the primary screens 48 including a spreader and a bafile although usually one screen 14 is needed where three screens 48, 49 are needed.

The gluten from the washer 56 is separated out on the screen 1'4, and drops down and is led into a Moyno pump 78 which forces the gluten through apertures in avpipe 19 into a steam-heated cylindrical devitalizing tank 15' where it is agitated by propeller blades 16 on a vertical shaft H, at a temperature of about 190 F. to 212 F.

The apertures found satisfactory were A; inch to inch in diameter, and the tank was of such a size that the gluten remained in it on an' average of ten minutes plus another ten minutes when similarly treated in a second devitalizer 85, so that it is broken into suitable fragments, for the subsequent centrifuge, saw A inch, but not very fine.

The propeller blades 16 are found to work the secondary washer 56 through a hot water main 82.

Under the conditions given the tackiness of gluten produced by insufficient devitalizing is avoided, and no further benefits seem to be obtained by devitalizer treatment beyond a total of twenty minutes.

The contents of the devitalizer T5 are shown as receiving fresh hot water from a main 15a and as drawn olf from above the level of the propeller blades 76 through a pipe 84 which delivers the contents by gravity a little way down in the second similar devitalizer tank 85 provided with a similar propeller 86 and heated to the same temperature and delivering its contents, after an average period of ten minutes, through a pipe 81, similar to the pipe 84, to a continuous Bird centrifuge 88 in which the gluten (eX cept the very fine particles equal to about 6% of the gluten) is separated from the accompanying water, reducing the moisture content to about 75%.

The water efiluent from the centrifuge carrying this fine gluten is shown as carried back by a pipe 90 and pump 9| to the beginning of the process and used as hot water for mixing the initial .dough at the tank 25a. For controlling the temperature of the return water, there is shown a cooling tank 94. The gluten recovered from the Bird centrifuge may be dried In the improved form shown herein, the gluten recovered in the Bird centrifuge 88 drops through conduit 95 on a conveyor, preferably a screw conveyor, diagrammatically shown at 36, which carries a load of previously dried gluten, thus mixing the two.

The load of mixed gluten is carried along past an opening diagrammatically indicated at 3?, so that a part, usually about half, of the mixed gluten drops on a second conveyor 38 which carries it off for final drying.

To efifect this final drying of the separated mixed gluten it is shown as carried by a third conveyor 99 to a rotary dryer Hill, where the whole of the thus separated gluten is finally dried.

The dried gluten is diagrammatically shown as carried by a blower IGI to a cyclone separator I02 which is shown as delivering the dried gluten to a gluten bin I03 whence it passes at will to a bagger I04.

The mixed gluten which remains in the conveyor 96 is shown as separately dried to provide the stream of previously dried gluten. To provide this previously dried gluten the mixed gluten which passes the opening 91 is shown as delivered to a conveyor I05 which delivers the mixed gluten to a second rotary dryer I65 where the mixed gluten is dried.

This lot of the dried gluten is shown as delivered to a cyclone separator I6? by a blower I08, and then falling into a temporary bin I09 which delivers it to the conveyor iii; to provide the stream of previously dried gluten.

The opening 9'! may be set to pass various desired proportions of gluten for final drying as conditions warrant.

The water required for feeding the gluten by the Moyno pump 18 may come from a tank Iii) which temporarily receives water from the Bird centrifuge 88, through a pipe II I which delivers the water to a constant level tank i 52. The tank I I2 is shown delivering the water by a valved pipe II3 to the pump 18.

In the alternative the gluten may be dried according to the procedure now to be described and illustrated in the accompanying drawing (Fig. 2).

In the alternate form shown (Fig. 2) the gluten recovered in the Bird centrifuge 88 drops into a conveyor I I4 which carries it to a roller press l :5. Such. a press is found to remove one-fifth to onethird of the water in the gluten, reducing the water content of the wet mass to about 66%. If the gluten is still too sticky for efiicient drying, a few per cent of previously dried gluten may now be added.

The pressed and partly dried gluten is shown as then fed by a chute I I3 into the end of rotary steam tube drier I I? provided with an escape I Hi for gases and steam, including a trap Us for gluten carried in the gases.

A blower I2!) is shown as blowing the dried gluten delivered from the drier Ill to a cyclone separator 52!. The gluten is then shown as passing on from the cyclone E2! to an automatic weigher I22 and into a silc A bagger I2 may receive gluten from chute i255 at the bottom of the silo I23.

Another arrangement for handling the gluten which is more satisfactory under some conditions is to take the gluten from the screen is following the second agit tion tank 56' and deliver it by a pipe 5 13 to an extruding device I2? of the meat grinder type and then delivering the strings of extruded gluten by gravity (diagrams 8 matically whown by a pipe I23) to a hot water preliminary devitalizer I29.

Here the gluten is shown agitated by a small motor driven side entering propeller I30, and from this the gluten flows through the valve I3I to the devitalizer I5, and thence as if from the Moyno pump.

To avoid blocking of the downward feed of flowin the bins It and 54 by bridging of the flour as sometimes happens in the conical or funnel shaped bottom I32 (Fig. 1) of the bins, the bins are shown as provided with baffle II made up of freely swinging baflie plates I33, I35, I35, preferably of smooth metal. It has been found satisfactory to provide three rows I36, I31, I38 of bafiie plates I33, I34, I35, each row consisting of side walls I39 of the bins I3 and I4, though close to the walls and are each hung by short chains Hill, depending from cross bars I4I. The cross bars may be set to hold the plates higher in the bin than a flour bridge would arch to.

As a result any bridge of fiour that tends to form is cut by three smooth vertical surfaces so that flour slips down from between two of the surfaces, and when it slips down the plates swin in, the thrust ends of the incipient bridge (:01- lapse, and flour feeds down through the valve I8 unhindered.

The plan view of the screens 14 in Fig. 5, shows the vibrating screens I4, with the spreaders I42 above them delivering the gluten bearing liquid over end canvas bafiies M3 to receive the shock of the on-coming stream, and collecting the gluten in chutes Hi4 for delivery to the devitalizer it below it.

The starch-bearing wash water is delivered to the pipe by a funnel or tray I45 beneath its screens l4.

The various water and starch water conduits and pipes may include automatic temperature and level indicators and controls, only partially indicated to avoid complexity in the drawings.

The best results have been obtained when an anti-foaming agent was delivered to the first and secondary washers. Several agents have proved almost equally useful, such as di-butyl phthalate, octyl alcohol, foamicide of Wyandotte Chemic-al Corp. and diafoam made by Resinous Products Co. of Pittsburgh, Pa.

The operation of the plant shown may be summarized as follows: Flour and water are formed into a dough in the conveyor 24, the dough is admixed with more water in the agitator and wash- The resulting suspension is flowed on to the screens 48 which screen out the gluten agglomerates from the starch water, and the latter is carried off by a pipe SI to storage or fermentation.

The screened out gluten is further agitated in a washer 53, and screened out of the water on screens id, converted into strings, and washed in hot water in the successive devitalizers T5 and 85, filtered in the filter 88- and carried to a dry ing system including the conveyor 9%.

Here the oncoming wet gluten is admixed with previously dried gluten coming from a secondary drier I96, and part is carried to a final dryer IUD, where the process may end with the gluten ready for packing. 1

It will be seen that a highly efficient method" and apparatus are provided for the recovery of starch and gluten from wheat products which have proved so difficult to handle in the past, and the gluten is found to be purer than the gluten hitherto available commercially. Moreover by varying the process the starch may be recovered at will either as starch or as partially converted to sugar to facilitate subsequent fermentation. The gluten is shown as reduced to strings when freed from its associated starch, and thus well adapted to be quickly and efficiently dried.

In the form described excellent gluten is efficiently obtained from durum wheat, which is often richer in gluten than other wheats and at the same time is usually cheaper when sold as durum wheat flour.

As various changes may be made in the form, construction and arrangement of the parts herein without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. In the process of producing gluten and alcohol from durum wheat the steps which comprise mixing durum wheat flour with about an equal amount of ordinary type wheat flour, admixing said mixed fiours with water carrying some fine gluten particles to make a dough of about equal parts of water and flour, feeding and mixing the dough, further feeding the dough from a delay pool beyond said first feeding and mixing, again feeding the dough beyond a second delay pool, adding the dough to further water after a delay in a third delay pool, agitating the dough-water mixture to form agglomerates of gluten adapted to be retained on a thirty-mesh sieve, separating out the gluten by sieving the mixture and sending the separated starch water to fermentation and rectification.

2. The process of separating gluten from starch contained in durum wheat which comprises admixing durum wheat flour with ordinary type wheat flour having a higher percentage of starch so that the mixture contains about 50% of durum flour, making a dough of the mixed flour with an equal part of water, allowing the dough to stand in a quiet pool for a short interval, mixing the dough further, allowing the further mixed dough to stand in a quiet pool, mixing one part of the dough with four parts of added water, agitating the mixture by circulation to agglomerate contained gluten to form particles retainable on a BO-mesh sieve, and screening out the gluten agglomerates on a 30-mesh sieve 3. In the process of producing gluten and alcohol from durum wheat the steps which comprise mixing durum wheat flour with about an equal amount of ordinary type wheat flour, admixing said mixed flours with water carrying some fine gluten particles to make a dough of about equal parts of water and flour, feeding and mixing the dough, further feeding the dough from a delay pool beyond said first feeding and mixing, again feeding the dough beyond a second delay pool, adding the dough to further water after a delay in a third delay pool, agitating the dough-water mixture to form agglomerates of gluten adapted to be retained on about a 30-mesh sieve, and separating out gluten agglomerates.

4. A process as claimed in claim 3, in which the temperature of the first mentioned added Water is such as to give the dough a temperature of about F.

5. The process of separating. gluten from starch contained in durum wheat which comprises admixing durum wheat flour with ordinary type wheat flour so that the mixture contains about 50% of durum flour, making a dough of the mixed flour with about an equal part of water, allowing the dough to stand in a quiet pool for a short interval, thereafter mixing the dough, allowing the mixed dough to stand in a quiet p001, mixing about one part of the dough with about four parts of added water, circulating the mixture to agglomerate contained gluten to form particles retainable on about a 30-mesh sieve, and separating out said gluten particles.

ACTON KEITH KILANDER.

REFERENCES CITED The following references are of record in the file of this patent: I

UNITED STATES PATENTS Number Name Date 340,705 Duryea Apr. 27, 1886 538,794 Rockteschel May 7, 1895 1,052,845 Ponndorf Feb. 11, 1913 1,535,811 Briggs Apr. 28, 1925 1,745,716 Rynders Feb. 4, 1930 1,845,847 Reuther Feb. 16, 1932 1,927,313 Hagen et a1 a- Sept. 19, 1933 2,070,286 Lissauer et al Feb. 9, 1937 2,090,187 Credo Aug. 17, 1937 2,144,333 Hagen Jan. 17, 1939 2,213,668 Dundas et a1 Sept. 3, 1940 2,388,902 Callaghan Nov. 13, 1945 2,418,621 Callaghan Apr. 8, 1947 FOREIGN PATENTS Number Country Date 107,603 Australia June 1, 1939 OTHER REFERENCES Jour. Am. Chem. Soc., 35: 1635-1643 (1913) Industrial and Engineering Chemistry, Feb. 1943, vol. 35, No. 2, pages 133 to 137, by Stark et al.

Osborne The Vegetable Proteins, Longmans, Green and Co., London (1924), page 2.

Shewfelt et al., "Separation of Starch and Gluten from Wheat Flour, Canadian Chemistry & Process Industries, July 1944, pages 502' and 519. 

1. IN THE PROCESS OF PRODUCING GLUTEN AND ALCOHOL FROM DURUM WHEAT THE STEPS WHICH COMPRISE MIXING DURUM WHEAT FLOUR WITH ABOUT AN EQUAL AMOUNT OF ORDINARY TYPE WHEAT FLOUR, ADMIXING SAID MIXED FLOURS WITH WATER CARRYING SOME FINE GLUTEN PARTICLES TO MAKE A DOUGH OF ABOUT EQUAL PARTS OF WATER AND FLOUR, FEEDING AND MIXING THE DOUGH, FURTHER FEEDING THE DOUGH FROM A DELAY POOL BEYOND SAID FIRST FEEDING AND MIXING, AGAIN FEEDING THE DOUGH BEYOND A SECOND DELAY POOL, ADDING THE DOUGH TO FURTHER WATER 